As President Barack Obama exhorts Americans to get behind a coherent energy policy, a new study shows the U.S. falling  behind in the race to develop new, clean sources of energy, according to a new study by Pew Charitable Trusts.

Last year, clean energy investment across the globe grew by 30%, to $243 billion last year, with China continuing to solidify its position as the world’s clean energy leader by investing a record $54.4 billion in 2010.

China’s investment represented a 39% increase from 2009, the new Pew Study said.  Germany was second in the G-20, up from third last year, after experiencing a 100% increase in investment, to $41.2 billion.

“The clean energy sector is emerging as one of the most dynamic and competitive in the world, witnessing 630% growth in finance and investments since 2004,” said Phyllis Cuttino, director of Pew’s Clean Energy Program.

“Countries like China, Germany and India were attractive to financiers because they have national policies that support renewable energy standards, carbon reduction targets and/or incentives for investment and production and that create long-term certainty for investors,” she said.

The United States, which had maintained the top spot until 2008, dropped another rung in 2010 to third, with $34 billion invested.

In a speech at Georgetown University, President Obama Wednesday outlined some of the steps he hopes to take as part of a new U.S. energy policy, some of them devoted to clean energy – including a switch to alternative power for the entire federal motor vehicle fleet – a total of 600,000 cars, trucks and crossovers – by 2015. (For more on the Obama energy plan, Click Here.)

The United Kingdom experienced the largest decline among the G-20, falling from fifth to 13th. The report suggests that uncertainty surrounding clean energy policies in these countries is causing investors to look elsewhere for opportunities.

Italy attracted $13.9 billion in clean energy financing last year, improving its global standing to fourth, up from eighth in 2009. Italy is the first country to achieve grid parity, or cost-competitiveness, for solar energy. For the first time, India joined the top 10 ranking, attracting $4 billion, a 25% increase.

Wind power continued to be the favored technology for investors at $95 billion. However, the solar sector experienced significant growth in 2010, with investments growing 53% to a record $79 billion and more than 17 gigawatts of new generating capacity globally. Germany accounted for 45% of global solar investments.

“Looking at global trends, the solar sector experienced the strongest growth among the various technologies, led by small-scale residential projects,” said Michael Liebreich, CEO of Bloomberg New Energy Finance.

Pew Charitable Trust also reported it had recruited former Michigan Gov. Jennifer Granholm, who will lead a campaign for a national clean energy policy that promotes and funds research and manufacturing for the wind, solar and advanced battery industries in the U.S.